Nowadays, the smart device, such as smart phone, smart watch or smart medical device, with large-screen monitor is common and makes user receiving messages easier than before. Moreover, not only the size and the function are important for the large-screen monitors, the visual appearance including the shape, the contour and the color is also a part which is paid attention to. A stellar exterior design and the manufacturing process thereof makes the large-screen monitor having individuation and attractive appearance in the same time. Among them, the large-screen monitor with three-dimensional shell is the most popular and attractive one which might lead the fashion and tread of future.
Currently used methods for manufacturing the three-dimensional shell and the pattern thereon of the smart device are described as follows: transfer printing and laser engraving after ink jet. Said transfer printing is preparing the pattern first and transferring the pattern to the target three-dimensional surface. Though the processing cost of transfer printing is low, however, the transfer printing technique has some drawback such as the slow processing speed, costly material, and the low resolution of printing. On the other side, as the name suggests, said laser engraving after ink jet is jetting the ink to the target three-dimensional surface first and then engraving the target three-dimensional surface to get the pattern by laser. This method costs high in material, equipment and processing and processes slow but with high printing resolution. The minimum resolution is up from 20 um.
Accordingly, how to provide a method to manufacture the three-dimensional shell and the pattern thereon with low processing and material cost, high processing speed and high printing resolution and a method to make colorful patterns on a three-dimensional and solid shell has become the major emphasis of the smart device firm. One technique is called photolithography which coats a photo-resist layer on the three-dimensional shell and uses light to transfer a geometric pattern to the resist layer on the curved shell. However, how to etch the three-dimensional shell by photo mask is the major direction of the related field.